Tā píngshí chénmò guǎyán, dàn sīxià lǐ hé'ǎi kě qīn.
He is usually quiet, but in private he is warm and approachable.
Tips
memory
Break it down: 和 (hé, harmonious) + 蔼 (ǎi, gentle/kind) + 可 (kě, can/able to) + 亲 (qīn, be close to). Literally: 'harmoniously gentle and able to get close to' — a person so warm you naturally want to approach them.
